Referring to FIG. 1, a conventional door hinge 1 disclosed in Taiwanese Utility Model Patent No. M412227 has a first connecting member 11, a second connecting member 12, a camshaft 13, a threaded member 14, a sliding member 15, a resilient unit 16, and a fluid chamber sleeve 17.
The second connecting member 12 is connected to a door panel (not shown). The camshaft 13 interconnects the first and second connecting members 11, 12, and is rotatable between a normal state and an inclined state. The threaded member 14 is screwed to one end of the camshaft 13 through the second connecting member 12 such that the camshaft 13 is fixed to the second connecting member 12. The sliding member 15 and the resilient unit 16 are mounted between the first connecting member 11 and the camshaft 13, such that there exists a gap between the sliding member 15 and the camshaft 13. The resilient unit 16 is capable of driving the camshaft 13 from the inclined state back to the normal state via the sliding member 15. The fluid chamber sleeve 17 is mounted to the first connecting member 11, and cooperates with the sliding member 15 to define a fluid chamber 171. The conventional door hinge 1 further has a fluid passage 18 that is in spatial communication with the fluid chamber 171 and the gap (between the sliding member 15 and the camshaft 13), such that a damping fluid which is in the fluid chamber 171 may be guided to flow in and out of the fluid passage 18 via the gap.
Therefore, when an external force drives the door panel and the second connecting member 12 to pivot relative to the first connecting member 11, the camshaft 13 is driven to rotate from the normal state toward the inclined state, thereby driving the sliding member 15 to compress the resilient unit 16. During this time, the damping fluid in the fluid chamber 171 flows into the abovementioned gap and slows down the movement of the sliding member 15 and the rotation of the camshaft 13, so that the pivotal movement of the second connecting member 12 and the door panel is slowed down as well. When the external force is eliminated, the sliding member 15 is driven by the restoring force of the resilient unit 16 to drive the camshaft 13 back to the normal state. At this time, the damping fluid in the gap is driven to flow back into the fluid chamber 171 via the fluid passage 18. In such a manner, the damping fluid produces a damping effect so that the rotation of the camshaft 13 and the pivotal movement of the second connecting member 12 and the door panel are slowed down to prevent abrupt opening and closing of the door panel.
In order to provide enough resilient force for driving the camshaft 13 back to the normal state, the resilient unit 16 of the conventional door hinge includes two resilient members 161, 162. However, as the resilient force of the resilient unit 16 increases, the external force needed to push the door panel open has to increase as well, which is rather inconvenient from a user's perspective.